《medicine》-itis (indicating an inflammatory disease)
「炎」 has another reading with different meanings.
flame; blaze
tonsillitis
キャンプファイヤーの炎を見た。
I watched the campfire flames.
炎が激しく燃え上がっていた。
The flames were burning fiercely.
彼の目には情熱の炎があった。
There was a flame of passion in his eyes.